1. Field of the Invention
This invention relates generally to fifth-wheel assemblies for coupling trailers to tractors and, more particularly, to an improved sliding fifth-wheel assembly which will automatically inform the operator of the vehicle when the trailer is positioned relative to the tractor so as to produce a desired drive axle weight to steering axle weight ratio.
2. Prior Art
It is well-known that by moving a trailer forward with respect to its associated tractor, the weight on the tractor's drive-axle will decrease and the weight on the steering axle will increase. While this results in better steering traction when driving under slippery road conditions, it requires greater steering effort on the part of the operator. In contrast, moving the trailer rearward with respect to its associated tractor will increase drive axle (rear axle) weight and decrease the weight on the steering axle. This reduces the effort required for steering and results in a softer ride for the operator. For this reason, fifth-wheels have been developed which include a lower half (i.e., that half which is fixed to the tractor) which may be either manually or pneumatically moved forward or rearward. This provides maximum tractor utilization for various lengths and types of trailers under various road conditions.
Adjustment is usually made by first either manually or pneumatically releasing a locking mechanism which secures the coupling shield thus permitting it to move either forward or rearward, setting the brakes on the trailer, driving the tractor forward or rearward until the tractor and trailer achieve a desired relationship, and then locking the fifth-wheel in place. Unfortunately, this process has, in the past, required that the fifth-wheel be visually monitored during the adjustment process in order to determine when the desired position and therefore the desired weight distribution has been achieved.